When is somebody considered an expert - 10,000 hours experience

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We recently encountered in the impeachment trial, a so called expert in foresics.  It turned out he was in the field, and trained only for 2 months only, not much to be called an expert

Malcolm Gladwell in his book "Outlier" said it needs 10,000 (roughly 10 years to be considered an expert

When is somebody an expert?